xnu-3789.70.16.tar.gz

[apple/xnu.git] / libsyscall / custom / __gettimeofday.s

diff --git a/libsyscall/custom/__gettimeofday.s b/libsyscall/custom/__gettimeofday.s
index 0076f49ce7ffc641206727adc8c324aa09bab66e..8712a20946250150e30f9f99697240631442fb88 100644 (file)
--- a/libsyscall/custom/__gettimeofday.s
+++ b/libsyscall/custom/__gettimeofday.s
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 1999-2007 Apple Inc. All rights reserved.
+ * Copyright (c) 1999-2016 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
@@ -11,10 +11,10 @@
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
- * 
+ *
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
+ *
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
@@ -22,36 +22,73 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
+ *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
-/* Copyright 1998 Apple Computer, Inc. */
 
 #include "SYS.h"
 
-#if defined(__i386__)
-
 /*
- *     This syscall is special cased: the timeval is returned in eax/edx.
+ * A third argument, of type uint64_t*, was added to the gettimeofday syscall
+ * for use cases that also want to know the mach_absolute_time that matches the
+ * time value returned.
+ *
+ * __gettimeofday takes the traditional two arguments.  It will zero out the
+ * third argument argument before entering the kernel, behaving like the old
+ * call.
+ *
+ * __gettimeofday_with_mach will pass it through and supporting kernels will
+ * copy-out the mach_absolute_time.  Old kernels will leave the pointed to
+ * value alone.
  */
+
+.private_extern ___gettimeofday_with_mach
+
+#if defined(__i386__)
+
 LABEL(___gettimeofday)
+    pushl      $0
+    pushl      12(%esp)
+    pushl      12(%esp)
+    calll      ___gettimeofday_with_mach
+    addl       $12, %esp
+    ret
+
+LABEL(___gettimeofday_with_mach)
     UNIX_SYSCALL_INT_NONAME(gettimeofday,0)
-       mov             4(%esp),%ecx
-       mov             %eax,(%ecx)
-       mov             %edx,4(%ecx)
-       xor             %eax,%eax
-       ret
+    /*
+     * <rdar://problem/26410029>
+     * If eax is 0, we're on a new kernel and timeval was written by the kernel.
+     * Otherwise, eax:edx contains the timeval and we marshal into timeval.
+     */
+    cmp     $0, %eax
+    je      2f
+    mov     4(%esp),%ecx
+    mov     %eax,(%ecx)
+    mov     %edx,4(%ecx)
+    xor     %eax,%eax
+2:
+    ret
 
 #elif defined(__x86_64__)
 
-/*
- *     This syscall is special cased: the timeval is returned in rax:rdx.
- */
+__SYSCALL(___gettimeofday_with_mach, gettimeofday, 3)
+
 LABEL(___gettimeofday)
+    movq   $0x0, %rdx // zero out third argument
+
     UNIX_SYSCALL_NONAME(gettimeofday,0,cerror_nocancel)
-    movq       %rax, (%rdi)
-    movl       %edx, 8(%rdi)
-    xorl       %eax, %eax
+    /*
+     * <rdar://problem/26410029>
+     * If rax is 0, we're on a new kernel and timeval was written by the kernel.
+     * Otherwise, rax:rdx contains the timeval and we marshal into timeval.
+     */
+    cmp     $0, %rax
+    je      2f
+    movq    %rax, (%rdi)
+    movl    %edx, 8(%rdi)
+    xorl    %eax, %eax
+2:
     ret
 
 #else